Geoff S

Posted by Frank Skilbeck on 21/02/2016 19:42:39: Must admit I've never hit my throttle cut switch while the model is in the air, but activate throttle cut as soon as the plane is down so it can be safely picked up. But some ESCs can be equipped with a suitable safety plug, like this, but you don't find these at the budget end. Well, not actually in flight but after launching my Phoenix 2k with my right hand I inadvertently caught the motor kill switch as I returned it to the transmitter Nothing much happened except the plane gently landed a few feet in front of me. On my Taranis I use the RH switch on top of the case (whichever that is, I haven't got my transmitter handy) as motor disabler together with a voice warning. I can't see my ever switching it off in actual flight and even if I did most often it wouldn't be a total disaster and easily corrected. I'll certainly look into the sticky throttle option though. Geoff

As Dom says, they're not mirrored like the Fun Cub and so can be driven from a single receiver channel via a Y-lead. Multiplex dropped off I think and Durafly learned from that as they have from the undercarriage which is far too floppy on the FC. In fact I think the Tundra undercarriage may be worth buying as a spare to fit on own design/built models. Geoff

If you feel you may need to recharge your transmitter or receiver packs at the field then a better option might be just to carry spare ready charged batteries. Otherwise you would need to have not only a charger but the means to power it (ie a 12 volt battery, which is a heavy lump). You could use your car battery but that's not something I'd want to do. Actually, I'd be surprised if you needed to recharge at all if you were fully charged already. Geoff

I don't use any US fitting with threads. I stick to known metric threads then there's less chance of errors with ill fitting parts. Geoff

I've had pretty well 100% satisfaction with HK. The only problem I had was an ignition set that arrived just after we went on a 3 week holiday and the Post Office sent it back because they only keep 'signed for' packets for a week. So not really HK's fault. I've seen several Durafly Vampires flying very successfully so it's not a universal problem. Don't write off HK too soon but pursue your problem on the lines suggested above and I think you'll get it sorted out. Geoff PS I think all engines can be referred to as motors but all motors (ie electric ones) cannot conventionally be referred to as engines Edited By Geoff Sleath on 17/02/2016 20:40:12 Edited By Geoff Sleath on 17/02/2016 20:44:24

No, it's very easy on the DB Moth. 2 3mm screws for each wing and a couple of self tappers to attach the undercarriage rear legs to the bottom wing. The interplane struts just hook on at the bottom and are secured at the top by sliding a 14 gauge rod (I use stainless bike spokes because I have a 100s of them) through eyes on the wing and struts. They're kept in place by a rubber band. It's as quick as it can be and gets round the main objection of biplanes very well. It may take a little longer if you opt to fit flying and landing wires (shirring elastic is enough for effect) but not much. Geoff

That's certainly the place for the battery assuming you can connect it easily to the esc. Mine angles down from the back of the firewall into the fuel tank compartment and is therefore a bit further back. You could also perhaps combine the battery box with the motor mounting. One thing to watch out for is if you need to angle the battery to get it into its place. The leading edge of the bottom wing might make a straight entry difficult. There's space for the esc in the fuel tank space but for both cooling and wiring it might be a good idea to put a large hole in the firewall. Looking good. Almost tempts me to buy another that I could build from scratch Geoff

It applies to most clubs I've ever joined - motor cycle, cycle, sailing and model aircraft. It just makes life a lot easier for the volunteers who keep the clubs going. My wife has been the treasurer and sometime membership secretary of our local cycle club (Derby Mercury) for about 25 years and to handle upwards of 400 memberships renewing throughout the year would be a nightmare. She already spends a lot of time in January handling cheques and cash as it is. When I was membership secretary a few years back we only had about 90 members and that was bad enough. Geoff

Thanks, Scott. Mine's a very old kit I was given part complete and needed a lot of correction. I'm sure yours will build into a better Moth. Yes, mine's electric. The battery (a 4000 mAH LiPo) slides into the fuel tank area through the hatch visible at the back of the cowl. It still needs a lot of lead but I'm hoping to move the CoG gradually further back and save weight. The DB Moth's CoG is quite a bit further forward than most other kits (and the full size). If I was building one from scratch, as you will be, I'd make arrangements to get the battery further forward into the cowl itself. Mine weighs 3kg and flies fine at that but I've only had one 6 minute test flight which used about 55% of the battery. Geoff

I'll subscribe to this. I got mine ready to test fly back in December and just managed to find a day before New Year. I also have scale tail controls. It's still not 'finished', of course. There's always a bit more that could be done - like finishing off the simulated rib stitching and tail plane struts. Didn't bother with a sprung undercarriage and had no problem with any bounce on landing relying on the squishy tyres Geoff

Whilst clearing out a lever arch file I came across an article I must have down loaded and printed back in 1999/2000. It's a presentation by Jim Bourke to the 1999 Electric Performance Rally in Dallas USA. I thought it may be of interest. Watts/lb 30 to 50 for ROG 40 to 60 for sport aerobatics 70 to 100 for 'good' aerobatics Not much different from now and we're getting more useful output power for input watts than they got with NiCads and brushed motors. Orme's Law 1 cell (NiCad) per 35 square inches of wing area for sports planes 1 cell per 50 square inches for trainers So with LiPos it's 1 cell/ 100 square inches for sports planes and 1/150 square inches for trainers. Wing Loading 1 lb/square foot for very light planes 1 lb/square foot for sport planes The writer gives a lot of importance to wing loading and aims for the lower rating. Power Rules (for propellers) Power is proportional to diameter ^4 Power is proportional to rpm^3 Power is proportional to pitch These are rough approximations but he claims them to be near enough. eg doubling rpm means the power (and presumably the battery/motor/esc current) is increased by a factor of 8 Theoretical Pitch Speed mph = pitch (inches) x rpm/1000 This is again a rough approximation (level flight, I assume) and in practice the actual speed is a bit less than this. Duration = 120/current in amps Amps = 120/duratiom This assumes a 2 aH battery so much the same as our 2200mAh LiPos Obviously adjust for capacity. He does mention a 'miracle' battery with a capacity of as much as 4 AH! We're lucky.   Propeller diameter and pitch The diameter to pitch ratio should be between 1.5:1 and 1:1 He suggests 1:1 is most efficient and it seems popular sizes like 12x6 are not very. I can't think what he would say about the 13x4 on my DB Tiger Moth. Trouble is with higher pitch the pitch speed goes right up as well which isn't what I want with a scale biplane. I think this issue touches on the static thrust measurement arguments, too ... oops! Jim's Quick and Dirty Propeller Guesser D^5 = I/(V^2 x Kv^3) Where D is prop diameter in feet, I is the target current, V is the battery voltage and KV is the motor's rpm/volt. He suggests that pitch is less of an issue because it affects the power much less than the diameter. In any case it will be greater than half the diameter according to one of the earlier 'rules'.   The whole paper is much longer than my post and offers several examples to support the rules. I think a lot of it is relevant to modern electric flight. They were struggling in 1999 (I know I was) and it was relatively expensive. Just thought it might be of interest to some of you. Geoff   Edited By Geoff Sleath on 15/02/2016 15:51:44

I also have 30 years worth of the Motor Cycle Sport tucked away up in the loft. Every copy from when it first appeared as a magazine rather than in newspaper format in about 1963 until I stopped taking it years later. I really should find a good home for them but I think they're more valuable than a digital record and certasinly more attractive in feel and appearance. Geoff

I don't think the I has disappeared in paper form though its birth parent the Independent is about to. We subscribe to the paper editions of the Guardian and we've taken it and the Observer for about 40 years. I would greatly miss my breakfast without it propped up as I eat my toast and drink my coffee. My wife and I bond over the crossword as we eat our evening meal (actually it's an exercise of her demonstrating how much cleverer she is than I am). I suppose it's inevitable but I'm hoping I'll be beyond caring when my Guardian is only available on line. I subscribe to the digital edition of RCME but I find it difficult to read in its current format. My vdu is, like most, in landscape mode but the magazine (like all) is in portrait mode. So when I enlarge the image to be easy to read I can't view a whole page in one go despite having screen area to spare on each side, which I find more irritating than I thought I would. My vdu is roughly 500 x 300 mm so not very small. There is no way I would want to either to read RCME or a newspaper on a smartphone or tablet with screen so tiny as to make text even smaller except in an emergency. Geoff

Do you feel confident towing a glider without a tow release on the tow plane? It's OK if nothing goes wrong but what do you do if the glider cable release fails? Perhaps it never does? Quite impressed how well the Tundra coped. Mine's still untested Geoff

Tony, the acetone may take a while to effect the release and it will also help if you slide a scalpel blade down the side as John suggests. I succeeded in removing a big plastic moulding from a Multiplex Blizzard wing by application of acetone with a little mechanical assistance. It does work. Give it time and a few more applications. Leave it soaking in overnight. Geoff

Have you tried using a known electric model programme but binding to the Phoenix receiver. I know the controls may be all wrong but the esc should work. That would narrow it down to something in the Phoenix programme rather than any hardware fault. Geoff

Posted by Stephen Jones on 12/02/2016 20:05:20: Hi, Continuing on with my interest in tandem wings. What are they and do they hold any merit in todays aviation. Well , Tandem meaning two . And most planes have two wings don't they . In a tandem wing design both wings add to the lift of the plane as opposed to a covenantal plane where the rear tail plane gives negative lift . But just to say both wings add to the lift does not mean they both give equal lift . Take a look here. The most well known being the HM 14 flying flea . I suppose you know that this wing arrangement has certain failings because of the proximity of the front and rear wings. I know Ian Redshaw was very cagey when he test flew his half scale example and relied more on throttle than 'elevator' control. As a long time tandemist (two wheel, pedalled variety) I share your interest Though, come to think of it, someone lent us a tandem tricycle for a day in France and we did 70 enjoyable miles on it. Geoff Geoff

I know it's too late for you this time but I always fully fit the hinges, then run the thin cyano in. Trying to do it the way you attempted this time is always to risk its grabbing before you want it to. I then always pin both sides with cocktail sticks, again glued in place with thin cyano after fitting. You can release the hinges with either a propriety cyano release fluid (mine in called Unstick from 5 Star but they're hard to deal with right now) or acetone. Nail varnish remover is acetone based but I'm not sure if it's full strength. Geoff

Those Poundland lithium batteries on multiple cards are very poor. We tried them in my wife's cycle computer but they needed replacing every 2 or 3 weeks whereas the proper, more expensive ones last well over a year. Geoff

I was much, much more careful with the Tiger Moth and everything was checked and rechecked several times. I guess I was getting a bit blase with the Riot after a few 100 flights. No, I was using a Frsky V8R4-II with my Taranis. Somehow the weight of the aileron channel had been changed from 100 to -100 as I discovered when I examined it carefully. It must have been me when I was messing with the settings with gloves on in the cold and wind. In any case I should have checked the controls before I took off as I usually do. It was short exciting flight Anyway the Riot didn't owe me a lot and I like it so much I've got a new airframe and it's ready to go again. Geoff

I converted to Win 10 a few weeks ago and Phoenix, which was already running on Win 7 continued to work after my upgrade. So it wouldn't appear to be a Win 10 fault as such. I'm running the latest version of Phoenix I updated recently from the Phoenix web site. Geoff

Yes my first 35Mhz radio transmitter was a Micron. I gave all of it away a few years ago. I used to live in Long Eaton but that was may years before I became interested in RC. Dave and Mark Heaton are members at Ashbourne though I haven't seen either of them for a year or so. The RC scene has changed dramatically even in the relatively short time I've been involved. There was once room for small manufacturers like Micron and the first sail winch I bought for model yacht racing, a Whirlwind, was made and designed by David Andrews who was chairman of the club I joined in Loughborough. This has been the result of the changes in electronics which has generated not only ever more sophisticated (and cheaper) products but, at the same time, enabled the means to buy worldwide at the click of a mouse button. Having been in at the start when I was given the opportunity to play those new-fangled microprocessors at work when it was all at the knife and fork, nuts and bolts level when we had to read the data sheets to get them to work, I appreciate the differences. It's all a bit high level now and doesn't seem quite so much fun The plight of the aged since the beginning of time! Geoff

After you've fixed the hinges, which I assume are the flat plastic type fixed with cyano, just drill through each side with a 2mm drill and push a cocktail stick through and run a little more thin cyano in to fix them. They'll never come out in any normal use ie without crashing and the wood breaking Geoff

Just a hop, step and a jump from me then. Kilburn is only a couple of miles or so from Heage. Ashby's probably 25 miles from us though I did once cycle to Foremark Reservoir to work on our dinghy and had to nip over to the chandlers in Ashby for some parts but I was pretty fit in those days Geoff

Ah, Goodyear's, now I remember It sounds rather like Wayland's in Heanor but I think a little bigger. Wayland's was almost total chaos staffed by Wayland himself, and a nicer bloke you'd be hard to find. As I heard him once explain to salesman over the phone he kept the shop more as a hobby and something to do rather than as a means of making money. Well, he was well past the normal retirement age. His wife kept half the shop for handicrafts. They eventually retired for real. One of the best shops in the Derby area was Spondon Supermodels but that closed probably 10 years ago. The last reasonably accessible shop was Hobbystores in Beeston which closed about a year ago. Geoff